SQL SELECT... WHERE with REPLACE - worried that it's inefficient

Question

In SQL Server 2005, I have a Product search that looks like:

select ProductID, Name, Email 
from Product
where Name = @Name

I've been asked to ignore a couple "special" characters in Product.Name, so that a search for "Potatoes" returns "Po-ta-toes" as well as "Potatoes". My first thought is to just do this:

select ProductID, Name, Email 
from Product
where REPLACE(Name, '-', '') = @Name

...but on second thought, I wonder if I'm killing performance by running a function on EVERY candidate result. Does SQL have some optimization magic that help it do this kind of thing quickly? Can you think of anything easier I might be able to try with the requirements I have?

Answer 1

More standards-based: You could add a new column, e.g., searchable_name, precalculate the results of the REPLACE (and any other tweaks, e.g., SOUNDEX) on INSERT/UPDATE and store them in the new column, then search against that column.

Less standards-based: Lots of RDBMS provide a feature where you can create an INDEX using a function; this is often called a functional index. Your situation seems fairly well suited to such a feature.

Most powerful/flexible: Use a dedicated search tool such as Lucene. It might seem overkill for this situation, but they were designed for searching, and most offer sophisticated stemming algorithms that would almost certainly solve this problem.